[R] Superimpose exponential density function to histogram

[Rui Barradas]

Hello,

Try

curve(dexp(x, rate=lambda), add=TRUE)

Hope this helps,

Rui Barradas

Em 07-05-2013 14:18, Manta escreveu:
> Dear all,
>
> I have a large vector of durations (in seconds) and I create an histogram as
> follows:
>
> hist(durations,breaks=500,xlim=c(0,2000),main="",xlab="Duration
> (Seconds)",ylab="Frequency (%)",prob=TRUE)
>
> Next, I would like to superimpose the exponential distribution with the
> maximum likelihood estimate of lambda. To do so, I first calculate get the
> estimate of lambda and then try to add the curve in the following way (with
> error):
>
> library(MASS)
> lambda=fitdistr(durations,"exponential")$estimate
> curve(rexp(10000,rate=lambda),add=TRUE)
>
> Error in curve(rexp(10000,rate=lambda),add=TRUE) : 'expr' must be a
> function, or a call or an expression containing 'x'.
>
> So I need to have an 'x', OK. But doing this does not work either:
> curve(dexp(durations,rate=lambda),add=TRUE)
>
> What am I doing wrong?
>
>
>
>
>
> --
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>
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